The advance of genomics has led to the definition of thousands of human genes as well as the identification of a significant proportion of genes in other non-human organisms. We have coupled these advanced genomic resources with modern engineering and informatics capabilities to establish a cDNA microarray center laboratory. Microarrays allow for the simultaneous monitoring of gene expression changes relative to control in thousands of genes. It is the goal of this lab to aid intramural and extramural investigators in understanding how environmental agents may affect gene expression, and thus increase our knowledge of the mechanism of action of such agents. In the past year progress has been made to investigate the gene expression signatures associated with exposure to oxidant stressors (ie radiation, dioxin) and non-genotoxic carcinogens, such as peroxisome proliferators, phenobarbital, arsenic, and estrogen and oxidant stressors in defined human tissue culture models as well as in tissues from derived from animals exposed in vivo.